The benefits of wind energy have long been harnessed as a useful power source. Now a Californian company aims to increase the energy output of this resource. Rather than situating windmills on the ground, as tradition dictates, Makani Power has created a tethered wind turbine that generates power by flying aloft in large circles, much the way a kite does. The Makani Airborne Wind Turbine flies at between 800 and 1,950 feet above ground level, meaning that it stays well below normal commercial and civilian aviation. At the same time, it flies at an altitude above that of most birds, meaning that any potential harm to flying creatures is minimized, it says. Meanwhile, at these heights the wind is stronger and more consistent than that which terrestrial wind farms encounter, and 90 percent of the material used in conventional wind turbines can be eliminated. The video below illustrates the premise in more detail: In 2011 Makani Power built and tested a 30kW prototype, known as Wing 7. So far, benefits it touts over traditional windmills include 50 percent cost savings, a 10 percent reduction in mass, 50 percent more energy production, and a lower environmental impact, the company says. Energy entrepreneurs: one to get involved in?